Safety and pharmacokinetics of single doses of aclidinium bromide, a novel long-acting, inhaled antimuscarinic, in healthy subjects

Abstract

Aclidinium bromide is a novel antimuscarinic being developed for the treatment of chronic obstructive pulmonary disease. The objective of this Phase I study was to determine the maximum tolerated dose (MTD) as well as the tolerability, safety and pharmacokinetics of aclidinium in healthy subjects. 16 healthy subjects were randomized to receive 5 single ascending doses of aclidinium 600 - 6,000 microg or placebo inhaled via dry powder inhaler, with 7 day washouts. Safety measurements included adverse events (AEs), physical examination, vital signs, pupillometry examination, clinical laboratory tests, and 12-lead electrocardiogram. Pharmacokinetic parameters of aclidinium and its metabolites were assessed. The incidence of AEs was comparable between aclidinium and placebo at all doses. Most AEs were mild to moderate with no dose-related or anticholinergic/cardiac AEs. At doses >or= 2,400 microg, only 13 AEs were considered treatment related. Aclidinium (600 - 6,000 microg) did not produce function-limiting or severe AEs in >or= 50% of subjects; hence, the prospectively-defined MTD was not established. Aclidinium was rapidly converted in plasma into alcohol and carboxylic acid metabolites, and was no longer detectable after 3 hours post-dose for all doses. At lower doses, aclidinium was quantifiable only up to 1 hour post-dose in the majority of subjects. Maximum plasma concentrations for aclidinium were reached within 5 - 7 minutes (all doses) and declined rapidly. Mean elimination half-lives of aclidinium > 2,400 microg were approximately 1 hour. AUC and Cmax increased proportionately up to 4,800 microg. Aclidinium appears to be safe and well tolerated in single doses of 600 - 6,000 microg.